Riku has the power of darkness, and a weapon holding phenomenal power. As shown in KH2, he can shoot energy blasts and harness shields. He also has some badass aerial attacks. Rikku has multiple dress spheres that include Gunner, Black Knight, White Mage, Alchemist, and Berserker. She also has her special dress sphere, Machina Maw. Rikku seems to have more gadgets at her disposal, but Riku's best and most powerful attack is Dark Aura, the signature technique he uses in Kingdom Hearts: COM. Also, Riku can take the form of Xehanort's heartless. Rikku vs Xenahort's Heartless; That'd be a really tough fight for Rikku. Keep in mind she helped defeat Vegnagun...she's one of the hottest girls in the Final Fantasy franchise btw.